What do you need to know about Rhogam?


So you’re pregnant! Congratulations! That’s great. You’ve gotten all your labs done and you found out you’re A-negative. Your doctor wants you to get a shot of Rhogam when you’re around 28 weeks. You’re rightly concerned and trying to figure out why you’re just now learning about this possible blood incompatibility between you and baby. You probably even ask does everyone know about this? Well this blog is for you, we’ll be diving into Rhogam, the reasons behind it and whether you even need. 

As you probably already knew everyone has a blood type and you’re either negative or positive. Positive and negative don’t really mix, just like we learned in math “like goes with like” and vice versa. There’s an antigen or “foreign body” on positive blood types. This antigen is not on negative blood type and when they are introduced or cross paths, they could cause a reaction. When are some possibilities that they could accidentally mix? Well when you get a blood transfusion with blood that doesn’t match yours or when you’re pregnant! What usually happens is a mother who has a negative blood type, has a significant other with a positive blood type and the baby has a positive blood type just like dad. 

During pregnancy it’s natural for a small amount of baby’s blood to enter your blood stream. When this happens your bodies’ immune system will recognize baby’s blood as a foreign substance. Your immune system will then produce antibodies that will try to harm baby. It could make baby really sick and anemic.  Introducing Rhogam! Rhogam is a solution of antibodies collected from plasma donors. Way back in the day physicians came up with a solution. Think of Rhogam as Harry Potter’s invisible cloak. It blocks the mother’s immune system from attacking the baby. Without this Rhogam, mothers with a negative blood type that had more than one baby with positive blood type were at risk for becoming “sensitize”. What this means is their body already recognize the foreign substance once and know to go on the attack from the beginning. These babies are at risk for miscarriage, brain damage, or newborn death. 

When should you receive Rhogam? Typically, around 28 weeks and once again after the baby is born. Other times you could receive Rhogam include any reason that you and your baby’s blood type will mix. This includes abdominal trauma, an invasive procedure, maternal or fetal bleeding during pregnancy, an ectopic pregnancy, or unfortunately for a miscarriage. When do you not need Rhogam? If your baby has been confirmed to be a negative blood type. 

Still have more questions? Feel free to reach out to your health care provider. They’re also the ones that will be making sure you get Rhogam on time.

Marie Mathurin Certified Nurse Midwife

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